In certain machining applications, it is sometimes desirable to execute independent axial motions of elements in the tooling at a single station. For example, this is required to machine concentric features on a part, with separate independently advanced cutting tools located in the same station used to machine these features. This is done in the instance of machining valve stem guide bores and corresponding valve seats in engine cylinder head with separate cutting tools located in the same station.
This is advantageous to machine both the valve stem guide and the valve seat at a single station, so since the concentricity of the seat and bore may be more easily maintained, and this also reduces the number of separate machining stations required.
Arrangements are known in which a valve seat finishing tool and reamer are concentrically mounted at a single station, with the reamer axially advanced independently of the spindle assembly by which the tooling is rotated, and also rotated at a different speed than the valve seat finishing tool in order to maintain the valve stem guide bores.
This independent axial motion of the reamer has been accomplished by a draw bar mounted in the spindle assembly carrying a reamer holder.
There are a number of other applications requiring such independent motion of an element, some of which involve a plurality of motions of a single cutting tool. Examples of these instances are automatic tool wear compensation arrangements and other dual motions of a single tool driven by a single spindle.
There also presently is an increased need for so called "flexible" machining equipment in which the tooling of high production machines may be changed quickly, such as for conducting operations on differently configured parts. In conventional transfer machines, the tooling is dedicated to a specific part and the transfer line must be retooled by a rebuilding of the machine to be adapted to the manufacture of another part.
In "flexible" machining applications, automatic tool changers have heretofore been employed which allow an exchange of tooling assemblies automatically in a spindle assembly at a given machining station. However, heretofore no tooling coupling arrangement has been provided for a tooling assembly having a separately moveable element mounted therein, which must be connected to a separately moveable actuator member in the spindle assembly.
As, for example, to separately advance a reamer from a valve seat finishing tool both contained in the tooling assembly; to operate a plurality of motions of a single tool in the tooling assembly.